See the link below to find where to UNCHECK the option to leave a message on the server.
By the way, if you haven't installed the most recent service pack for Office 2007, please do so.. It fixes a number of issues such as you are seeing.
Hope this helps.
I have been receiving the same message multiple times from my internet mail server on my laptop. when I send and receive the server sends three copies of each new message. what is causing this andd how do I fix it